A mandrel is a rotatable, cylindrical apparatus upon which fiberglass and related materials can be wound to produce pipes, cylindrical tanks and similar articles. After the fiberglass hardens, the article is removed from the mandrel by sliding it in a longitudinal direction parallel to the mandrel axis. Because the hardened article is in close contact with the mandrel over a considerable surface area, the removal of the article can be a difficult process. One known expedient is to provide means for collapsing or reducing the diameter of the mandrel after the article hardens. By collapsing the mandrel, the contact between the article and the mandrel is broken, and the article can then be removed in a longitudinal direction.
A further technique to facilitate removal of articles is to support the mandrel in a cantilevered manner with one end unobstructed, so that hardened articles can be removed over the unobstructed end without disassembly of the support apparatus. However, the length of mandrel that can be cantilevered is limited by the mandrel's weight, and the mandrel's weight is, in turn, dependent upon the complexity of the internal mechanism, if any, for reducing the mandrel diameter. Although designs for collapsible mandrels have been proposed, none of the prior designs has resulted in a collapsible mandrel that is sufficiently light in weight to permit the effective use of a cantilevered support for the larger mandrel sizes.